This disclosure generally relates to components for aircrafts, and in particular aircraft components having low ASTM E662 smoke density and good 60 second vertical burn properties.
Flame retardant (FR) polymers and polymer blends, for example polycarbonates and polycarbonate blends with UL V0 and 5VA and B Underwriters Laboratories flammability ratings are widely prepared and used, especially in a wide variety of electrical and electronic applications. Conversely, only a very limited set of polycarbonates are used in aircraft applications particularly interior parts such as windows, partition walls, ceiling panels, cabinet walls, storage compartments, galley surfaces, light panels, and the like. All of these applications have stringent flammability safety requirements that the polycarbonates must meet. For example, the safety standards for aircraft and transportation systems used in the United States include an ASTM E662 smoke density test and 60 second vertical burn tests including flame time, burning drip time and burn length specified in Federal Aviation Regulation (FAR) 25.853. Requirements can vary per manufacturer, but typically parts with a surface area of less than 1 square feet have to meet requirements on ASTM E662 smoke density and 60 second vertical burn, while larger parts have to fulfill these requirements and additional requirements on OSU (Ohio State University) heat release. In another example, the aircraft manufacturer Airbus has smoke density and other safety requirements set forth in ABD0031. In the event of a fire, components made from materials having these properties can increase the amount of time available for escape and provide for better visibility during a fire.
Despite extensive investigation, a need still exists for improved materials that meet governmental and aircraft manufacturer flame safety requirements and that have good mechanical properties, including high stiffness, high strength, good impact, and good processability.